ST7735 Based TFT on SAMD21, possible?

Looking for a library to run a TFT module based on ST7735 chip such as this module but for some reason I couldn't find any, whatever I tested wouldn't compile including retired Arduino TFT lib, Adafruit ST7735 and other....

show the code, there is nothing not to work

Sure, any specific library you want me to try?

this library works for me on all available arduino boards: UNO,NANO,MEGA,DUE,ESP8266,ESP32, RP2040 Pico, RP2040Pico W, MICRO...

I don't see any SAMD21 board on your list.

Have you tried TFT_eSPI?

the display works on a standard SPI port and if it works on a SAM3X processor, then what prevents it from working on an older SAM21

The following code generates an error:

#include <Adafruit_ST7735.h>
#include <SPI.h>
void setup() {}
void loop() {}

Error compiling for board Arduino MKR WiFi 1010.

All errors related to Adafruit_I2CDevice, for example:
'TwoWire' has not been declared
'TwoWire' does not name a type
'_wire' was not declared
and so on.

No idea, maybe I am doing something wrong.

I did now, same thing.

exit status 1
Error compiling for board Arduino MKR WiFi 1010.

Looking at the details of the screenshots I can see it's not the current version of
Adafruit-ST7735-Library so I wonder if you can send more details, maybe a link to the lib or what version you have there, or maybe upload the program you've run. Thanks!

I am writing a standard example for the arduino I have. Your arduino is not there, but I added the code for it. Try.
I compile.

/**************************************************************************
  This is a library for several Adafruit displays based on ST77* drivers.

  Works with the Adafruit 1.8" TFT Breakout w/SD card
    ----> http://www.adafruit.com/products/358
  The 1.8" TFT shield
    ----> https://www.adafruit.com/product/802
  The 1.44" TFT breakout
    ----> https://www.adafruit.com/product/2088
  The 1.14" TFT breakout
  ----> https://www.adafruit.com/product/4383
  The 1.3" TFT breakout
  ----> https://www.adafruit.com/product/4313
  The 1.54" TFT breakout
    ----> https://www.adafruit.com/product/3787
  The 1.69" TFT breakout
    ----> https://www.adafruit.com/product/5206
  The 2.0" TFT breakout
    ----> https://www.adafruit.com/product/4311
  as well as Adafruit raw 1.8" TFT display
    ----> http://www.adafruit.com/products/618

  Check out the links above for our tutorials and wiring diagrams.
  These displays use SPI to communicate, 4 or 5 pins are required to
  interface (RST is optional).

  Adafruit invests time and resources providing this open source code,
  please support Adafruit and open-source hardware by purchasing
  products from Adafruit!

  Written by Limor Fried/Ladyada for Adafruit Industries.
  MIT license, all text above must be included in any redistribution
 **************************************************************************/

#include <Adafruit_GFX.h>    // Core graphics library
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735
#include <Adafruit_ST7789.h> // Hardware-specific library for ST7789
#include "FontsRus/TimesNRCyr10.h" // https://github.com/immortalserg/AdafruitGFXRusFonts
#include <SPI.h>

uint32_t old_millis();

#if defined(ESP32) // Feather Huzzah32

#define HSPIs             // Дисплей на HSPI )SPI1)
#if defined(HSPIs)         // для ESP32 HSPI
#define TFT_CS        15  // GP13 - CS
#define TFT_RST       16  // GP14 - RESET
#define TFT_DC        17  // GP15 - A0
#define TFT_MISO      12  // GP12 - MISO (MISO, RX)
#define TFT_MOSI      13  // GP11 - SDA  (MOSI, TX)
#define TFT_SCLK      14  // GP10 - SCK
#else                     // для ESP32 VSPI (SPI0)
#define TFT_CS        5   // GP5  - CS
#define TFT_RST       20  // GP20 - RESET
#define TFT_DC        21  // GP21 - A0
#define TFT_MISO      19  // GP19 - MISO (MISO, RX)
#define TFT_MOSI      23  // GP23 - SDA  (MOSI, TX)
#define TFT_SCLK      18  // GP18 - SCK
#endif
/*
  #define TFT_CS         14
  #define TFT_RST        15
  #define TFT_DC         32
*/
#elif defined(ESP8266)
#define TFT_CS         4
#define TFT_RST        16
#define TFT_DC         5

#elif ( defined(ARDUINO_NANO_RP2040_CONNECT) || defined(ARDUINO_RASPBERRY_PI_PICO) || defined(ARDUINO_ADAFRUIT_FEATHER_RP2040) || \
      defined(ARDUINO_GENERIC_RP2040) )

// замаркировать если используем наоборот
#define SPI01             // Дисплей на SPIO1, NRF24L01 на SPI0 (выбор между SPI0 и SPI1)
#if defined(SPI01)        // для RP2040 SPI1
#define TFT_CS        13  // GP13 - CS              (hard - 13)
#define TFT_RST       10  // GP14 - RESET           (10)  
#define TFT_DC        11  // GP15 - A0              (11)  
#define TFT_MISO      12  // GP12 - MISO (MISO, RX) (hard - 12)
#define TFT_MOSI      15  // GP11 - SDA  (MOSI, TX) (hard - 15)
#define TFT_SCLK      14  // GP10 - SCK             (hard - 14)
#else                     // для RP2040 SPI0
#define TFT_CS        17  //5   // GP5 - CS               (hard - 17)
#define TFT_RST       20  //6   // GP6 - RESET
#define TFT_DC        21  //7   // GP7 - A0
#define TFT_MISO      16  //4   // GP4 - MISO (MISO, RX)  (hard - 16)
#define TFT_MOSI      19  //3   // GP3 - SDA  (MOSI, TX)  (hard - 19)
#define TFT_SCLK      18  //2   // GP2 - SCK              (hard - 18)
#endif

#elif (defined(_VARIANT_ARDUINO_STM32_)|| defined(_BOARD_GENERIC_STM32F103C_))
#define TFT_CS        PA4
#define TFT_RST       PB10
#define TFT_DC        PB11
#define TFT_MISO      PA6
#define TFT_MOSI      PA7
#define TFT_SCLK      PA5

#elif (defined(SAMD_MKRWIFI1010))
// SPI
#define TFT_CS        4
#define TFT_RST       5
#define TFT_DC        7
#define TFT_MISO      10
#define TFT_MOSI      8
#define TFT_SCLK      9
/*
// SPI
#define PIN_SPI_MISO  (10u)
#define PIN_SPI_MOSI  (8u)
#define PIN_SPI_SCK   (9u)
#define PIN_SPI_SS    (4u)
#define PERIPH_SPI    sercom1
#define PAD_SPI_TX    SPI_PAD_0_SCK_1
#define PAD_SPI_RX    SERCOM_RX_PAD_3

static const uint8_t SS   = PIN_SPI_SS;   // SPI Slave SS not used. Set here only for reference.
static const uint8_t MOSI = PIN_SPI_MOSI;
static const uint8_t MISO = PIN_SPI_MISO;
static const uint8_t SCK  = PIN_SPI_SCK;

// SPI1
#define PIN_SPI1_MISO    (27u)
#define PIN_SPI1_MOSI    (26u)
#define PIN_SPI1_SCK     (29u)
#define PIN_SPI1_SS      (28u)
#define PERIPH_SPI1   sercom4
#define PAD_SPI1_TX   SPI_PAD_0_SCK_3
#define PAD_SPI1_RX   SERCOM_RX_PAD_1
static const uint8_t SS1   = PIN_SPI1_SS;
static const uint8_t MOSI1 = PIN_SPI1_MOSI;
static const uint8_t MISO1 = PIN_SPI1_MISO;
static const uint8_t SCK1  = PIN_SPI1_SCK;

#define SPIWIFI_SS       PIN_SPI1_SS
#define SPIWIFI_ACK      NINA_ACK
#define SPIWIFI_RESET    (~NINA_RESETN)   // fixme! Inverted logic
*/
#else  // UNO, NANO

#define TFT_CS        10
#define TFT_RST       9
#define TFT_DC        8
#define TFT_MISO      12
#define TFT_MOSI      11
#define TFT_SCLK      13

#endif

// OPTION 1 (recommended) is to use the HARDWARE SPI pins, which are unique
// to each board and not reassignable. For Arduino Uno: MOSI = pin 11 and
// SCLK = pin 13. This is the fastest mode of operation and is required if
// using the breakout board's microSD card.

// For 1.44" and 1.8" TFT with ST7735 use:
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);
//Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST); //SOFT SPI не работает

// For 1.14", 1.3", 1.54", 1.69", 2.0" and 2.4" TFT with ST7789:
//Adafruit_ST7789 tft = Adafruit_ST7789(&SPI1,TFT_CS, TFT_DC, TFT_RST); //SPI1
//Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST); //SPI0
//Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST); //SOFT SPI


// OPTION 2 lets you interface the display using ANY TWO or THREE PINS,
// tradeoff being that performance is not as fast as hardware SPI above.
//#define TFT_MOSI 11  // Data out
//#define TFT_SCLK 13  // Clock out

// For ST7735-based displays, we will use this call
//Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);

// OR for the ST7789-based displays, we will use this call
//Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);


float p = 3.1415926;

#define maxString 100 // ограничиваем строку шириной экрана
char target[maxString + 1] = "";

char *utf8rus2(char *source)
{
  int i, j, k;
  unsigned char n;
  char m[2] = { '0', '\0' };
  strcpy(target, ""); k = strlen(source); i = j = 0;
  while (i < k) {
    n = source[i]; i++;

    if (n >= 127) {
      switch (n) {
        case 208: {
            n = source[i]; i++;
            if (n == 129) {
              n = 192;  // перекодируем букву Ё
              break;
            }
            break;
          }
        case 209: {
            n = source[i]; i++;
            if (n == 145) {
              n = 193;  // перекодируем букву ё
              break;
            }
            break;
          }
      }
    }

    m[0] = n; strcat(target, m);
    j++; if (j >= maxString) break;
  }
  return target;
}


void setup(void) {
  Serial.begin(115200);
  Serial.print(F("Hello! ST77xx TFT Test"));


  // Use this initializer if using a 1.8" TFT screen:
    tft.initR(INITR_BLACKTAB);      // Init ST7735S chip, black tab

  // OR use this initializer if using a 1.8" TFT screen with offset such as WaveShare:
  // tft.initR(INITR_GREENTAB);      // Init ST7735S chip, green tab

  // OR use this initializer (uncomment) if using a 1.44" TFT:
  //tft.initR(INITR_144GREENTAB); // Init ST7735R chip, green tab

  // OR use this initializer (uncomment) if using a 0.96" 160x80 TFT:
  //tft.initR(INITR_MINI160x80);  // Init ST7735S mini display

  // OR use this initializer (uncomment) if using a 1.3" or 1.54" 240x240 TFT:
  //tft.init(240, 240);           // Init ST7789 240x240

  // OR use this initializer (uncomment) if using a 1.69" 280x240 TFT:
  //tft.init(240, 280);           // Init ST7789 280x240

  // OR use this initializer (uncomment) if using a 2.0" or 2.4" SPI V1.2 240x320 TFT:
  //tft.init(240, 320);           // Init ST7789 240x320

  // OR use this initializer (uncomment) if using a 1.14" 240x135 TFT:
  //tft.init(135, 240);           // Init ST7789 240x135

  // OR use this initializer (uncomment) if using a 1.47" 172x320 TFT:
  //tft.init(172, 320);           // Init ST7789 172x320

  // SPI speed defaults to SPI_DEFAULT_FREQ defined in the library, you can override it here
  // Note that speed allowable depends on chip and quality of wiring, if you go too fast, you
  // may end up with a black screen some times, or all the time.
  tft.setSPISpeed(8000000); // установить скорость SPI

  Serial.println(F("Initialized"));

  uint16_t time = millis();
  // tft.setRotation(0); // разъём вверху
   tft.setRotation(1); // разъём слева
  // tft.setRotation(2); // разъём внизу
  //tft.setRotation(3); // разъём справа (ST7789)

  tft.invertDisplay(false);
  tft.cp437(true);                // не пропускаем 176 символ
  tft.fillScreen(ST77XX_BLACK);
  time = millis() - time;

  Serial.println(time, DEC);
  delay(500);

  // large block of text
  tft.fillScreen(ST77XX_BLACK);
  tft.setFont(&TimesNRCyr10pt8b);
  tft.setCursor(10, 20);
  tft.print(utf8rus2("Начали тест с русскими символами на графическом дисплее"));
  delay(3000);
  tft.fillScreen(ST77XX_BLACK);
  tft.setFont(); // выбор шрифта по умолчанию
  testdrawtext("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur adipiscing ante sed nibh tincidunt feugiat. Maecenas enim massa, fringilla sed malesuada et, malesuada sit amet turpis. Sed porttitor neque ut ante pretium vitae malesuada nunc bibendum. Nullam aliquet ultrices massa eu hendrerit. Ut sed nisi lorem. In vestibulum purus a tortor imperdiet posuere. ", ST77XX_WHITE);
  delay(3000);

  // tft print function!
  tftPrintTest();
  delay(4000);

  // a single pixel
  tft.drawPixel(tft.width() / 2, tft.height() / 2, ST77XX_GREEN);
  delay(500);

  // line draw test
  testlines(ST77XX_YELLOW);
  delay(500);

  // optimized lines
  testfastlines(ST77XX_RED, ST77XX_BLUE);
  delay(500);

  testdrawrects(ST77XX_GREEN);
  delay(500);

  testfillrects(ST77XX_YELLOW, ST77XX_MAGENTA);
  delay(500);

  tft.fillScreen(ST77XX_BLACK);
  testfillcircles(10, ST77XX_BLUE);
  testdrawcircles(10, ST77XX_WHITE);
  delay(500);

  testroundrects();
  delay(500);

  testtriangles();
  delay(500);

  mediabuttons();
  delay(500);

  Serial.println("done");
  delay(1000);
}

void loop() {
  tft.invertDisplay(true);
  delay(500);
  tft.invertDisplay(false);
  delay(500);
}

void testlines(uint16_t color) {
  tft.fillScreen(ST77XX_BLACK);
  for (int16_t x = 0; x < tft.width(); x += 6) {
    tft.drawLine(0, 0, x, tft.height() - 1, color);
    delay(0);
  }
  for (int16_t y = 0; y < tft.height(); y += 6) {
    tft.drawLine(0, 0, tft.width() - 1, y, color);
    delay(0);
  }

  tft.fillScreen(ST77XX_BLACK);
  for (int16_t x = 0; x < tft.width(); x += 6) {
    tft.drawLine(tft.width() - 1, 0, x, tft.height() - 1, color);
    delay(0);
  }
  for (int16_t y = 0; y < tft.height(); y += 6) {
    tft.drawLine(tft.width() - 1, 0, 0, y, color);
    delay(0);
  }

  tft.fillScreen(ST77XX_BLACK);
  for (int16_t x = 0; x < tft.width(); x += 6) {
    tft.drawLine(0, tft.height() - 1, x, 0, color);
    delay(0);
  }
  for (int16_t y = 0; y < tft.height(); y += 6) {
    tft.drawLine(0, tft.height() - 1, tft.width() - 1, y, color);
    delay(0);
  }

  tft.fillScreen(ST77XX_BLACK);
  for (int16_t x = 0; x < tft.width(); x += 6) {
    tft.drawLine(tft.width() - 1, tft.height() - 1, x, 0, color);
    delay(0);
  }
  for (int16_t y = 0; y < tft.height(); y += 6) {
    tft.drawLine(tft.width() - 1, tft.height() - 1, 0, y, color);
    delay(0);
  }
}

void testdrawtext(char *text, uint16_t color) {
  tft.setCursor(0, 0);
  tft.setTextColor(color);
  tft.setTextWrap(true);
  tft.print(text);
}

void testfastlines(uint16_t color1, uint16_t color2) {
  tft.fillScreen(ST77XX_BLACK);
  for (int16_t y = 0; y < tft.height(); y += 5) {
    tft.drawFastHLine(0, y, tft.width(), color1);
  }
  for (int16_t x = 0; x < tft.width(); x += 5) {
    tft.drawFastVLine(x, 0, tft.height(), color2);
  }
}

void testdrawrects(uint16_t color) {
  tft.fillScreen(ST77XX_BLACK);
  for (int16_t x = 0; x < tft.width(); x += 6) {
    tft.drawRect(tft.width() / 2 - x / 2, tft.height() / 2 - x / 2 , x, x, color);
  }
}

void testfillrects(uint16_t color1, uint16_t color2) {
  tft.fillScreen(ST77XX_BLACK);
  for (int16_t x = tft.width() - 1; x > 6; x -= 6) {
    tft.fillRect(tft.width() / 2 - x / 2, tft.height() / 2 - x / 2 , x, x, color1);
    tft.drawRect(tft.width() / 2 - x / 2, tft.height() / 2 - x / 2 , x, x, color2);
  }
}

void testfillcircles(uint8_t radius, uint16_t color) {
  for (int16_t x = radius; x < tft.width(); x += radius * 2) {
    for (int16_t y = radius; y < tft.height(); y += radius * 2) {
      tft.fillCircle(x, y, radius, color);
    }
  }
}

void testdrawcircles(uint8_t radius, uint16_t color) {
  for (int16_t x = 0; x < tft.width() + radius; x += radius * 2) {
    for (int16_t y = 0; y < tft.height() + radius; y += radius * 2) {
      tft.drawCircle(x, y, radius, color);
    }
  }
}

void testtriangles() {
  tft.fillScreen(ST77XX_BLACK);
  uint16_t color = 0xF800;
  int t;
  int w = tft.width() / 2;
  int x = tft.height() - 1;
  int y = 0;
  int z = tft.width();
  for (t = 0 ; t <= 15; t++) {
    tft.drawTriangle(w, y, y, x, z, x, color);
    x -= 4;
    y += 4;
    z -= 4;
    color += 100;
  }
}

void testroundrects() {
  tft.fillScreen(ST77XX_BLACK);
  uint16_t color = 100;
  int i;
  int t;
  for (t = 0 ; t <= 4; t += 1) {
    int x = 0;
    int y = 0;
    int w = tft.width() - 2;
    int h = tft.height() - 2;
    for (i = 0 ; i <= 16; i += 1) {
      tft.drawRoundRect(x, y, w, h, 5, color);
      x += 2;
      y += 3;
      w -= 4;
      h -= 6;
      color += 1100;
    }
    color += 100;
  }
}

void tftPrintTest() {
  tft.setTextWrap(false);
  tft.fillScreen(ST77XX_BLACK);
  tft.setCursor(0, 30);
  tft.setTextColor(ST77XX_RED);
  tft.setTextSize(1);
  tft.println("Hello World!");
  tft.setTextColor(ST77XX_YELLOW);
  tft.setTextSize(2);
  tft.println("Hello World!");
  tft.setTextColor(ST77XX_GREEN);
  tft.setTextSize(3);
  tft.println("Hello World!");
  tft.setTextColor(ST77XX_BLUE);
  tft.setTextSize(4);
  tft.print(1234.567);
  delay(1500);
  tft.setCursor(0, 0);
  tft.fillScreen(ST77XX_BLACK);
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(0);
  tft.println("Hello World!");
  tft.setTextSize(1);
  tft.setTextColor(ST77XX_GREEN);
  tft.print(p, 6);
  tft.println(" Want pi?");
  tft.println(" ");
  tft.print(8675309, HEX); // print 8,675,309 out in HEX!
  tft.println(" Print HEX!");
  tft.println(" ");
  tft.setTextColor(ST77XX_WHITE);
  tft.println("Sketch has been");
  tft.println("running for: ");
  tft.setTextColor(ST77XX_MAGENTA);
  tft.print(millis() / 1000);
  tft.setTextColor(ST77XX_WHITE);
  tft.print(" seconds.");
}

void mediabuttons() {
  // play
  tft.fillScreen(ST77XX_BLACK);
  tft.fillRoundRect(25, 10, 78, 60, 8, ST77XX_WHITE);
  tft.fillTriangle(42, 20, 42, 60, 90, 40, ST77XX_RED);
  delay(500);
  // pause
  tft.fillRoundRect(25, 90, 78, 60, 8, ST77XX_WHITE);
  tft.fillRoundRect(39, 98, 20, 45, 5, ST77XX_GREEN);
  tft.fillRoundRect(69, 98, 20, 45, 5, ST77XX_GREEN);
  delay(500);
  // play color
  tft.fillTriangle(42, 20, 42, 60, 90, 40, ST77XX_BLUE);
  delay(50);
  // pause color
  tft.fillRoundRect(39, 98, 20, 45, 5, ST77XX_RED);
  tft.fillRoundRect(69, 98, 20, 45, 5, ST77XX_RED);
  // play color
  tft.fillTriangle(42, 20, 42, 60, 90, 40, ST77XX_GREEN);
}

</details>

Thanks a lot for your help, problem solved by updating Adafruit_BusIO library.

Did my example work with your board?

Not as is, I am not sure what was the problem apart the fact that the fonts didn't load, so I used the library demo with the following setup:

#include <Adafruit_GFX.h>
#include <Adafruit_ST7735.h>
#include <SPI.h>

#define TFT_CS   10
#define TFT_RST  4
#define TFT_DC   5
#define TFT_MOSI 8 
#define TFT_SCLK 9

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);

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